yes ! style 5 is right. But more exact sample is above image. Namely it is follows

1. anker or arrow image is needed at bubble message's end.
2. time stamp is needed at below of bubble message.
3. Emoticon image can be inserted.
4. URL is detected and if mouse click, then browse is opened.
5. bubble message width is controlled according to window size's changing.
6. Vertical scrollbar is needed
7. Unread count number is needed at above of bubble message.

7. Unread count number is needed at above of bubble message. ---> this unread count is normally 1 in one-to-one chat room.

But in multiuser chat room, the unread count is greater more than 1 namely 5 , 4, 3, 2, 1, 0 ( 0 is not displayed, so hide unread count).
Because the unread count changes 5 to 4,3,2,1 in 6 user chat room, the unread count can be changable by program code and if the count is zero,
the count can be unvisible by program code.

I add the following

9. In bubble chat window, the opposite profile rounded image and name field is needed in opposite bubble message as the above attached chat image.
But in my bubble message, my rounded profile image and name field is not needed so do not displayed.

10. Select and Copy the bubble messages : As the above images show, mouse drag selection and right button copy popup menu is needed.
Selected bubble messages is rouned by shadowed box. And when right mouse click , copy popup menu is showed.
the popup menu itme have only one of copy menu.